Method of forming rigid structures



Jan. 18, 1955 F. w. STI-:1N

METHOD OF' FORMING RIGID STRUCTURES Original Filed Sept. 29, 1951 United States Patent() METHD F FORMING RIGID STRUCTURES Frederick W. Stein, Atchison, Kans.

Original application September 29, 1951, Serial No. 249,602. Divided and this application July 16, 1952, Serial No. 299,072

12 Claims. (Cl. 9 6) The present invention relates in gener-al t-o the assem bly of prefabrcated panels Iinto rigid. multipanel structures, and it deals more particularly with the prefabrication of a novel type of panel for use in such structures. This application is a division of my copending applica tion Serial No. 249,002 filed September 29, 1951.

Broadly speaking, an object of the invention is to provide a method and apparatus for simply and economically constructing lightweight but very sturdy panel structures which may be simple or relatively complex in shape, and which may employ panels that are either at or curved and, in either case, of any desired outline.

Another object is to provide a structure composed of lightweight panels of plywood or the like, permanently secured together without nails, screws or glue, the junction between adjoining panels comprising a rigid framework reinforcing the finished structure as well as the individual panels, and the joints between the panels being thoroughly weathertight and/or watertight.

A further object resides in the provision of a novel method and apparatus for bending -at plywood or similar nonmetallic flat sheet material into curved panels capable of retaining their curva-ture.

Still another object is to provide a structural panel having a metal frame outlining the panel and forming the margin thereof; the portion of the panel within the frame being of plywo-od or other suitable nonmetallic sheet material. An important collateral object is to provide a way of so bonding the frame to the nonmetallic central portion of the panel as to form a weathertfight and/ or watertight union therebetween.

While having many applicati-ons, my invention is especially well suited to the construction of boat hulls, and a particular object is to provide a lightweight, inexpensive skif or boat made of plywood or similar panels, at least some of which are curved, and all of which are joined together without screws, nails or glue to form a rigid, sturdy and watertight unit. According to the invention, the panel frames are of such strength as to eliminate the need for supplementary reinforcement of any kind, and they are so joined together as to make c'aulking unnecessary.

yClther objects of the invention, together with the fea tures of novelty whereby the objects are achieved, will appear in the course of the following description.

in the accompanying drawings which form a part of the specication and are to be read in conjunction therewith, and in which like reference numerals are used to indicate like parts of the various views:

lFig. 1 is a perspective view of a boat constructed in accordance with the method of and embodying the constructural features of the present invention.

Fig. 2 is 4a cross-sectional view taken along the line 2-2 of Fig. l in the direction of the arrows.

Fig. 3 is a fragmentary sectional View taken along the l'ine 3-3 of Fig. l in the direction of the arrows.

Fig. 4 is an enlarged sectional view taken through one of my prefabricated panels showing the structure of the frame member and the manner in which it is aixed to the edge of the panel.

Referring more particularly to the drawings, the boat hull shown in Fig. l comprises an essentially flat bottom panel 10, a flat stern panel 12, and a pair of curved side panels 14 and 16. Each panel is cut in one piece from at sheet stock which, as previously indicated, may lbe bonded plywood or other suitable nonmetallic sheet marice terial. The panels may be cut to the desired outline contour by sawing them from the sheet stock or, if identical boats are to be made in considerable quantity, by a machine stamping operation.

After being cut to the desired contour, each panel is enclosed in a' peripheral frame made of metallic pipe or tubing. In fabricating the frame, the pipe conveniently is cut into sections 18, each slightly longer than the side of the panel to which it is to be applied. All of the various pipe sections then are slit longitudinally to form channels that are generally C-shaped in transverse cross section (see Fig. 4). The width of slot 20 is made equal to, or very slightly greater than, the thickness of the panel proper, so that the edge of the latter can enter the slot and seat against the opposite inside wall of the channel when same is advanced over the edge in the direction indicated by arrow A. In the case of panels whose edges are curved (see, for example, the lateral edges of the bottom panel 10 of my boat), the channel is of course bent to conform with the curvature, either before or during the application of the channel to the edge in question.

When each edge of the panel has been inserted into the slot 20 of its corresponding channel and is seated -against the opposite inside wall of the channel as aforesaid, the mouth of the channel is squeezed tightly closed -upon the panel by applying a clamping force on the lateral sides of the channel (see arrows B). This may be carried out in a power press or by placing one side of .the channel against an anvil and striking the opposite side at closely spaced intervals with a hammer or mallet; or it may be accomplished in any other suitable fashion. This locks the channel very securely to the edge of the panel and makes a watertight joint at the points 21. At `the corners of the panel, the meeting ends of adjoining channels are cut diagonally to form a mitered joint 22, -and these ends are preferably welded or brazed together, n-ot only t-o preserve the continuity of the fluid seal, but -also to unite the various channel sections into a unitary -framle of great strength, completely circumscribing the pane The metallic-bound panels as thus prefabricated may Y. easily and quickly be assembled into the finished structure simply by arranging the various panels edge to edge in their correct rela-tionship and laying weld seams 24 and 26 along the meeting edges of adjoining panels. The frames of the separate panels thus are united to form a single rigid frame reinforcing 4the finished structure and giving it great strength. Moreover, the weld se-am between adjoining panels quite obviously forms a permanently watertight joint that completely eliminates the need for caulking, either atV the time of initial construction of the boat or at any time thereafter.

Heretofore, in the construction of boat hulls using large plywood panels for the sides or other portions of the hull which are curved, it has been necessary to employ specially designed temporary braces and forms, often of elaborate character, to shape the panels to the proper curvature and hold them in position while fabrication of the hull is being completed. My method and arr-angement makes such temporary braces and forms completely unnecessary and eliminates the time, labor and expense of installing and removing them after they have served their purpose.

Such is the case because, despite the tendency of plywood and similar nonmetallic sheet material t-o remain at and resist bending, my panels when bound in a peripheral metallic frame of the character disclosed can be bent to the desired curvature and will remain so bent under the influence of the metallic frame that is an integral part thereof. According to my invention, therefore, the side panels 14 and 16 of my boat are bent to the shape shown before being assembled into the final unit or, alternatively, may be so bent in the course of the assembly and welding operation.

Thus it will be seen that I obtain a boat hull which is light in weight but very sturdy and rigid. It is composed of relatively few structural components, these capable of being assembled quickly, easily and economically; and it is permanently watertight and free from the usual problems of caulking. Except for the channels forming the framework in the finished hull,

it is entirely nonmetallic but contains no nails or screwsthat can work loose nor any glue susceptible to deterioration over a period of time.

Very obviously my method and novel structural panels have wideV application beyond the field of boat building inasmuch as the panels may be made in the size and shape required for any specific installation and may be either at or curved as necessary. The panels are exceptionally strong despite their light Weight and they are very easily handled, all raw edges of the noninetallic central section being covered and concealed by the metallic frame which forms a smoothly rounded bead about the periphery of the panel.

From the foregoing, it will be seen that this invention is oney well adapted to attain all of the ends and objects hereinbefore set forth, together with other advantages which are obvious and which are inherent to the invention.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the appended claims.

Inasmuch as many possible embodiments of the invention may be made without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, l claim:

l. The method of making a boat hull, comprising the steps of cutting from non-rigid sheet material separate bottom, side and stern panels, the bottom panel having curved longitudinal edges, attaching a metallic binding strip to the marginal edges of each non-rigid panel to provide a stifening frame around same, bending .the frame-stiifened side panels to conform to the longitudinal edges of the bottom panel, positioning the panels edge to edge with the side and stern panels upstanding from the bottom panel, and welding the fran-ies of adjoining panels together at the meeting edges thereof.

2. The method of making a boat hull, comprising the steps of cutting from plywood sheet material sep arate bottom, side and stern panels, the bottom panel having curved longitudinal edges, attaching a metallic binding strip to the marginal edges of each plywood panel to provide a stiffening frame around same, forminga substantially watertight bond between each frame and its associated panel, bending the fratrie-stiffenedV side panels to conform to the longitudinal edges of the bottom panel, positioning the panels edge to edge with the side and stern panels upstanding from the bottom panel, and welding the metallic frames of adjoining plywood panels together at the meeting edges thereof.

3. The method of making a boat hull, comprising the steps of cutting from non-rigid sheet material separate bottom, side and stern panels, the bottom panel having curved longitudinal edges, attaching a metallic binding strip to the marginal edges of each non-rigid panel to provide a stiffening frame around same, forming a substantially watertight bond between each frame and its associated panel, bending the framed side panels to conform to the longitudinal edges of the bottom panel, positioning the panels edge to edge with the side and stern panels upstanding from the bottom panel, and connecting the frames of adjoining panels together with a continuous weld seam extending the full length of the meeting edges thereof. g

4. The method of making a boat hull, comprising the steps of cutting from sheet material separate bottoni, side and stern panels of complementary shape,'the bottom panel having curved longitudinal edges, slitting longitudinally a plurality of tubes each corresponding in length to one side of one of the panels, introducing each edge of each panel into the slot in the tube corresponding to that edge and positioning the ends of the tube so that the latter is substantially coterminous with said edge, clamping each tube to close the slot therein against opposite :faces of the panel, joining the meeting ends of adjacent tubesto form a continuous frame about the margin of each panel, bending the framed side panels to conform to the curvature of the longitudinal edges of the bottom panel, positioning the panels edge` toedge with the side and stern panels upstanding fromy the bottom panel, and welding the frames of adjoining panels together at the meeting edges thereof.

together at the meeting edges thereof.

5. The method of forming a rigid structure of the character described, comprising the steps of cutting from sheet material a pair of complementary panels, at least one of said panels having a curved edge, slitting longitudinally a plurality of tubes, each corresponding in length to one side of one of the panels, introducing each edge of each panel into the slot in the tube corresponding to that edge and positioning the ends of the tube so the latter is substantially coterminous with said edge, clamping each tube to close the slot therein against opposite faces of the panel, joining the meeting ends of adjacent tubes to form a continuous frame about the margin of each panel, bending one of the framed panels so that one edge thereof conforms to said curved edge of the other panel when said two panels are positioned in edge-to-edge relation with the faces of the panels at an angle to one another, placing said panels in said position, and welding the frames of adjoining panels together at the meeting edges thereof;

6. The method of assembling and connecting a plurality of non-metallic panels to form a rigid structure of the character described, comprising the steps of slitting longitudinally a plurality of metal tubes each corresponding in length to one side of one of the nonmetallic panels, introducing each edge of each panel into the slot in the tube corresponding to that edge and positioning the ends of the tube so the latter is substantially coterminous with said edge, joining the meeting ends of adjacent tubes to form a continuous metallic frame about the margin of each non-metallic panel, positioning the panels edge to edge to form the outline of the structure, and welding the frames of adjoining panels together at the meeting edges thereof.

'7. The method of making a construction unit of the character described, comprising the steps of cutting from a unitary sheet of material a panel of desired outline, slitting longitudinally a plurality of tubes, each corresponding in length to one side of the panel, introducing'each edge of the panel into the slit in the tube corresponding to that edge and positioning the ends of the tube so that the latter is substantially coterminous with said edge, clamping the tube to close the slot thercin against opposite faces of the panei, and joining the meeting ends of adjacent tubes to form a continuous frame about the margin of the panel..

8. The method of making a construction unit of the character described, comprising the steps of cutting from a unitary sheet of material a panel having at least one curved side, slitting longitudinally a plurality of tubes each corresponding in length to one side of the panel, bending each tube corresponding to a curved side of the panel to conform to the curvature thereof, introducing each edge of the panel into the slit in the tube corresponding to that edge and positioning the ends of the tube so the latter is Vsubstantially coterminous with said edge, clamping each tube to close the slot therein against opposite faces of the panel, and joining the meeting ends of adjacent tubes to form a continuous frame about the margin of the panel.

9, The method of making a construction unit of the character described, comprising the steps of cutting from a sheet of material a flat panel of desired outline, slitting longitudinally a plurality of metal tubes, each corresponding in length to one side of the panel, introducing each edge of the panel into the slit in the tube corresponding to that edge and positioning the ends of the tube so same is substantially coterminous with said edge, joining the meeting ends of adjacent tubes to form a continuous frame about the margin of the panel, and then bending the framed panel to set the metallic frame thereof in a permanently bent condition resisting the return of the panel to its normal at state.

l0. The method of assembling and connecting a pair of non-rigid complementary panels, at least one of which has a curved edge, to form a rigid Vstructure of the character described; comprising the steps of at" taching a metallic binding strip to the marginal edges of each non-rigid panel to provide a stiffening frame around same, bending one of the frame-stitfened panels so that one edge thereof conforms to said curved edge of the other panel when the two panelsV are positioned in edge-to-edge relation with the faces of the panels at an anglerto one another, Vplacing said panels in said position, and welding the frames of the adjoining panels 11. A method as in claim 10, including the step of forming a substantially watertight bond between each frame and its associated panel.

12. The method of assembling and connecting a pair of non-rigid complementary panels, at least one of which has a curved edge, to form a rigid structure of the character described; comprising the steps of attaching a metallic binding strip to the marginal edges of each non-rigid panel to provide a stilfening frame around same, forming a substantially watertight bond between 10 each frame and its associated panel, bending at least one of the frame-stiifened panels so that one edge thereof conforms to said curved edge of the other panel when the two panels are positioned in edge-to-edge relation with the faces of the panels at an angle to one another,

placing said panels in said position, securing the frames of the respective panels rigidly to one another and forming a watertight bond between the respective frames at the meeting edges of the panels.

References Cited in the le of this patent UNITED STATES PATENTS 741,362 Ohnstrand Oct. 13, 1903 994,128 Corliss June 6, 1911 1,761,451 Ohnstrand June 3, 1930 2,030,072 Peschel Feb. 11, 1936 2,423,670 Winslow July 8, 1947 2,515,161 Hall July 11, 1950 15 2,572,623 Hoppenstrand Oct. 23, 1951 

